In modern paintshops rotary atomisers are conventionally used for series coating of components, such as motor vehicle body parts, which apply a spray jet of a coating composition (e.g. liquid paint) onto the components to be coated by means of a rotating bell cup. Further, a shaping air ring may be arranged at the end face of such a rotary atomiser, which shaping air ring annularly surrounds the bell cup shaft and at its end face comprises a ring of shaping air nozzles with a large number of shaping air nozzles distributed annularly over the circumference, out of which a shaping air stream may be discharged towards the spray jet from behind, in order to shape the spray jet.
In one particular construction of such a rotary atomiser, the bell cup is partially encased, i.e. the shaping air ring surrounds the outer circumferential surface of the bell cup in the rear area of the bell cup, such that the shaping air ring displays axial overlap with the bell cup. A disadvantage of this construction, however is that “clearing air” is absolutely essential for preventing soiling of the rear of the bell cup.
In another construction of such a rotary atomiser, on the other hand, an annularly encircling gap is located in the axial direction between the shaping air ring and the bell cup, in the region of which gap the bell cup shaft is exposed and may therefore become soiled. With this construction problems may also arise if the rotary atomiser is cleaned in an automatic cleaning apparatus, since cleaning fluid may then penetrate into the annular gap between the shaping air ring and the bell cup.
Accordingly, there is a need for an improved rotary atomiser.